Systems and methods for air temperature control using A2L refrigerants

Abstract

The present invention provides a heating, ventilation, and air-conditioning (HVAC) system using an A2L refrigerant and a method of installing the HVAC system in a building. The HVAC system includes an indoor unit having a heat exchanger that uses an A2L refrigerant, a blower, an outdoor unit, an A2L control board, and one or more A2L sensors configured to detect an amount of A2L refrigerant. In one or more embodiments, the indoor unit is electrically coupled to the blower, the A2L control board, and the outdoor unit. Also, in one or more embodiments, the A2L control board is also electrically coupled to the blower and the one or more A2L sensors.

What is claimed is: 
     
       1. A system for controlling air temperature in a building, the system comprising:
 an outdoor unit disposed outside the building; 
 an indoor unit disposed inside the building, the indoor unit comprising:
 a heat exchanger that uses an A2L refrigerant; 
 a blower disposed within the indoor unit; 
 an indoor control board electrically coupled to the blower and the outdoor unit; 
 one or more A2L sensors configured to detect an amount of the A2L refrigerant in the indoor unit; 
 an A2L control board electrically coupled to at least the one or more A2L sensors, the indoor control board and the blower; 
 
 wherein:
 each of the one or more A2L sensors comprises a bus connector input, a bus connector output, a sensor relay electrically disposed between the bus connector input and the bus connector output, and a sensor feedback port electrically disposed between the sensor relay and the bus connector output. 
 
 
     
     
       2. The system of  claim 1 , wherein the A2L control board is configured to power on the blower and power off the indoor control board and the outdoor unit when the one or more A2L sensors detect the amount of the A2L refrigerant exceeds a leak threshold. 
     
     
       3. The system of  claim 2 , wherein:
 the A2L control board is configured to power off the indoor control board and the outdoor unit by opening a first relay; and 
 the A2L control board is configured to power on the blower by closing a second relay. 
 
     
     
       4. The system of  claim 3 , wherein:
 the blower includes a blower motor; 
 the A2L control board is directly coupled to an input lead on the blower motor; 
 when the second relay of the A2L control board is closed, the lead on the blower motor is configured to receive 24 volts of alternating current; and 
 the blower motor is configured to power on when it receives 24 volts of alternating current on the lead on the blower motor. 
 
     
     
       5. The system of  claim 3 , wherein:
 a first default orientation for the first relay of the A2L control board is open; 
 a second default orientation for the second relay of the A2L control board is closed; and 
 if the A2L control board loses power, the first relay and the second relay are configured to revert to the first default orientation and the second default orientation, respectively. 
 
     
     
       6. The system of  claim 2 , wherein:
 the A2L control board further includes a buzzer and an LED; and 
 the A2L control board is configured to power on the buzzer and LED when the one or more A2L sensors detect the amount of the A2L refrigerant exceeds the leak threshold. 
 
     
     
       7. The system of  claim 1 , wherein:
 the one or more A2L sensors are disposed within the indoor unit; 
 the indoor unit further includes an evaporator coil; and 
 the one or more A2L sensors are coupled to the evaporator coil. 
 
     
     
       8. The system of  claim 7 , wherein:
 the one or more A2L sensors include a first A2L sensor and a second A2L sensor; 
 the first A2L sensor and the second A2L sensor are electrically coupled to the A2L control board; and 
 the first A2L sensor and the second A2L sensor are coupled in series to the A2L control board. 
 
     
     
       9. The system of  claim 1 , further comprising a thermostat, wherein the thermostat is directly electrically connected to the indoor unit and is directly electrically connected to the outdoor unit. 
     
     
       10. The system of  claim 9 , wherein:
 the outdoor unit further includes an outdoor control board; and 
 the thermostat is directly electrically coupled to the indoor control board and the outdoor control board. 
 
     
     
       11. A method of installing an air temperature controller in a building, the method comprising:
 disposing an outdoor unit outside the building; 
 disposing an indoor unit inside the building, the indoor unit having a heat exchanger that uses A2L refrigerant; 
 disposing a blower within the indoor unit; 
 disposing an indoor control board within the indoor unit; 
 electrically coupling the indoor control board to the blower and the outdoor unit; 
 disposing one or more A2L sensors within the indoor unit, the one or more A2L sensors configured to detect an amount of the A2L refrigerant within the indoor unit; and 
 electrically coupling an A2L control board to at least the one or more A2L sensors, the indoor control board and the blower 
 wherein:
 each of the one or more A2L sensors comprises a bus connector input, a bus connector output, a sensor relay electrically disposed between the bus connector input and the bus connector output, and a sensor feedback port electrically disposed between the sensor relay and the bus connector output. 
 
 
     
     
       12. The method of  claim 11 , further comprising:
 detecting the amount of the A2L refrigerant exceeds a leak threshold using the one or more A2L sensors; and 
 after detecting that the amount of the A2L refrigerant exceeds the leak threshold:
 powering on the blower using the A2L control board; and 
 powering off the indoor control board and the outdoor unit using the A2L control board. 
 
 
     
     
       13. The method of  claim 12 , further comprising:
 powering off the indoor control board and the outdoor unit by opening a first relay using the A2L control board; and 
 powering on the blower by closing a second relay using the A2L control board. 
 
     
     
       14. The method of  claim 13 , further comprising:
 coupling the A2L control board to an input lead on a blower motor of the blower, wherein the blower includes the blower motor, wherein the blower motor is configured to power on when it receives 24 volts of alternating current on the input lead of the blower motor. 
 
     
     
       15. The method of  claim 13 , further comprising:
 if the A2L control board loses power:
 reverting the first relay to a first default orientation; and 
 reverting the second relay to a second default orientation, wherein:
 a first default orientation for the first relay of the A2L control board is open; and 
 a second default orientation for the second relay of the A2L control board is closed. 
 
 
 
     
     
       16. The method of  claim 12 , further comprising:
 powering on a buzzer and an LED when the one or more A2L sensors detect the amount of the A2L refrigerant exceeds the leak threshold, wherein the buzzer and the LED are disposed on the A2L control board. 
 
     
     
       17. The method of  claim 11 , further comprising:
 disposing the one or more A2L sensors within the indoor unit; and 
 coupling the one or more A2L sensors to an evaporator coil, wherein the indoor unit includes the evaporator coil. 
 
     
     
       18. The method of  claim 17 , further comprising:
 electrically coupling a first A2L sensor and a second A2L sensor in series to the A2L control board, wherein the one or more A2L sensors include the first A2L sensor and the second A2L sensor. 
 
     
     
       19. The method of  claim 11 , further comprising:
 directly electrically connecting a thermostat to the indoor unit; and 
 directly electrically connecting the thermostat to the outdoor unit. 
 
     
     
       20. The method of  claim 19 , further comprising:
 electrically coupling the thermostat directly to the indoor control board of the indoor unit; and 
 electrically coupling the thermostat directly to an outside control board of the outdoor unit.